Computation of Earnings per Share - Net loss per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Computation of Earnings per Share
Net loss	$ (3,141)	$ (1,060)	$ (938)	$ 228	$ (4,201)	$ (710)
Shares outstanding:
Weighted-average common shares outstanding (in shares)	21,470		21,537		21,495	21,551
Diluted shares outstanding (in shares)	21,470		21,537		21,495	21,551
Net loss per share - basic (in dollars per share)	$ (0.15)		$ (0.04)		$ (0.20)	$ (0.03)
Net loss per share - diluted (in dollars per share)	$ (0.15)		$ (0.04)		$ (0.20)	$ (0.03)